Run, despite and because life is complicated.

Hold on guys! This one is for the lady runners. Alright you can read it, but you can never unlearn this information, which may be a good thing if you have women in your life and I hope that you do in some way because we’re pretty awesome.

One of my new runners misheard something I was talking about and believed I was saying something about running during the menstrual cycle. Even though I wasn’t, she wanted to know how being on your period impacts your running, so this one is for you, Charity my girl.

The menstrual cycle is twenty-eight days long on average. The first fourteen days is called the Follicular phase and the second fourteen days is called the Luteal phase. During the follicular phase, the uterine wall thickens and prepares to become pregnant, estrogen levels increase and your body tries to conserve glycogen and relies more on fat stores for energy, serotonin levels drop and cortisol levels rise, causing cravings for sugar and fats, which help balance out moods imbalanced by the increase in hormones.

Sugar and chocolate cravings the week before and during your period are common. Cravings are typically a sign that your body is in need of something. Some women become more sensitive to insulin during their menstrual cycle and when the blood sugar levels drop they crave sweets.

A chocolate craving can be instigated by low iron and/or magnesium levels. Low magnesium levels can cause imbalances in electrolytes and muscle cramps. It’s not menstruation that causes low iron levels, the myth lives on, but it could be running. There are newer theories, which suggest each time our foot hits the ground we break red blood cells and lose iron. Another theory, is that a hormone that’s released in response to inflammation inhibits the uptake of iron.

During the Luteal phase, your plasma volume reduces by 8%, this causes an increase in your body temperature and slows down the sweating process. As if that’s not enough, the lower plasma thickens your blood making it more difficult to shuttle around fuel and oxygen, which of course, reduces energy levels. The lower plasma affects recovery time since your body is working harder to get oxygen and fuel to tired or injured muscles.

By the time you reach the luteal phase, you’ve likely put on a few pounds and your hormones are at their highest causing cramping, bloating, lower back pain, and headaches and then you can’t, or shouldn’t, take iburprophen because of the risk of kidney damage and other things (white willow bark and Aleve are recommended). Then ovulation happens over the next three to five days, then the blood begins and continues for five to seven days.

When you think about this, it’s not surprising to find out that your running performance can be affected by your monthly visit from Auntie Flow. So ladies, be aware there will be fluctuations in your performance caused by your cycle, keeping a training diary will help you pin point a pattern of changes and plan for them.